BUENOS AIRES , Argentina -LRB- CNN -RRB- -- More than 10,000 charred bone fragments were found buried at the site of a former Argentine government detention center , the first find of its kind at one of the secret centers , Argentine officials said .

Bones were unearthed during a seven-month search at an ex-detention post in La Plata , Argentina , officials said .

Searchers said they also found a wall with more than 200 bullet holes and an `` important quantity '' of spent ammunition shells on the ground nearby . In some cases , bullets were still lodged in the wall .

The announcement was made Tuesday at a news conference by government officials and representatives of the Argentine Forensic Anthropology Team , better known as EAAF , the initials of its name in Spanish .

A team of six professional anthropologists and support crew said it believed the remains were human , but it was unable to determine how many bodies the fragments represented .

`` I ask the forgiveness of family members , because I can imagine what the mothers and all who are gathered here will feel , but what we are about to show is not to detail the genocide but so that we have proof for the trials that are to come , '' said Sara Derotier de Cobacho , secretary of human rights for Buenos Aires province .

`` But let us not forget , '' she said in a statement , `` that behind every clandestine center there were the names of the repressors . ... So it is very important for all citizens to know those names . ''

The detention center was among those used in Argentina during the country 's `` Dirty War , '' which started in 1976 when a group of generals staged a coup and started a vicious crackdown against anyone considered a subversive .

By the time civilian control of the government resumed in 1983 , up to 30,000 Argentines had been abducted and taken to the secret government detention centers , where they were tortured and killed . They are widely called `` los desaparecidos , '' or `` the disappeared . ''

Thousands more people were abducted and killed by right-wing dictatorships in other South American countries during the 1970s and 1980s , particularly in Chile and Uruguay .

The bone fragments in Argentina were unearthed during a seven-month search at the former detention post in the city of La Plata , near Buenos Aires .

In 25 years of searching , this was the first time that human remains were found at a former detention center , said Luis Fondebrider , president of the EAAF .

`` We 've worked throughout the country and have always found remains in cemeteries , never outside , '' Fondebrider said in the release .

The conference was called , he said , because of the extraordinary nature of the find .

`` We usually do n't hold press conferences about our work or what we find , '' Fondebrider said . `` But we understand that the magnitude of what we have found where the Clandestine Center of Arana was located merits that sometimes we show partial results . ''

The searchers determined that bodies had been burned inside graves along with tires , combustibles and other material , Fondebrider said .

`` The possibilities of identifying some of these remains is low because of the state they are in , '' Fondebrider said .

The searchers will start analyzing the remains next year and are working with two prominent forensic genetic laboratories that specialize in working with remains that are in poor condition , he said .

Lending an official air to Tuesday 's proceedings , Carlos Stornelli , minister of security for the province of Buenos Aires , and Pablo Buruera , mayor of La Plata , also attended the news conference .

`` We are looking for the truth so we can attain justice and construct , from there , the memory of our 30,000 ` desaparecidos , ' '' Derotier said .

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Remains believed to be human ; number of bodies unknown , officials say

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Detention center among those used in Argentina 's 1976-1983 `` Dirty War ''

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Tens of thousands said to have been abducted , killed during `` Dirty War ''